Evaluation of a new ultra-rapid hand drier in relation to hand hygiene

Abstract number: 1733_1209

Snelling A.M., Saville T., Stevens D.G., Beggs C.B.

Objectives: Handwashing is a key element of infection control in the clinical and domestic settings. Whilst much research focuses on antibacterial wash products, or increasing compliance, little attention has been paid to the drying step. However, washing does not always remove 100% of contaminants, and can increase levels of commensal bacteria on the skin surface. The new AirbladeTM drier uses two high pressure air `knives' to strip water from still hands. Drying takes ~10 seconds. Conventional warm air driers rely on evaporation from the skin and often take ≥30 s with rigorous hand rubbing to achieve a satisfactory effect. The study aimed to compare the two types of drier in terms of residual bacterial load on hands.

Methods: The Airblade (Dyson Ltd) was tested against 2 conventional warm air driers widely used in the UK. 14 (7M, 7F) volunteers took part. In study (A) hands were contaminated by handling uncooked chicken. Washing was performed using the Euro-standard handwash (EN1499:1997) + non-medicated liquid soap. After using a drier, the fingers of each hand were pressed onto a strip (10×4 cm) of sterile aluminium foil. Bacteria transferred to foil were eluted into MRD + soap inactivator, and enumerated on TSA plates. Volunteers repeated the protocol with each machine, in random order. Study (B): clean hands were washed in the same way but without soap. Drying was performed with the machines +/- hand rubbing. Agar contact plates were used to enumerate bacteria on palms, fingers, fingertips before and after drying.

Results: In study (A) bacterial transfers of 0107 cfu/hand were observed. For a set drying time of 10 s the Airblade led to significantly less bacterial transfer than with the other driers (p < 0.05). When the latter were used for longer (3035 s) the trend was for the Airblade to still perform better, but results were not as significant (p > .05). In study (B) rubbing hands whilst using the driers counteracted the reduction in overall bacterial numbers at all anatomical sites. When hands were held still, there was no statistical difference between the driers.

Conclusions: If hands are not dried properly after washing, transfer of commensals or remaining contaminants to other surfaces is more likely to occur. The Airblade was superior to the conventional driers for reducing transfer. Its short drying time should encourage greater compliance with hand drying and hence help reduce the spread of infectious agents by the hand-borne route.